If everything dies except for the engine, start by looking at the wiring that runs through your firewall.

Dear Car Talk

Dear Car Talk | Apr 01, 1999

Dear Tom and Ray:

I have recently purchased a used 1994 Pontiac Bonneville SSEi. It has 92,000 miles on it and seemed to run fine, until last night. My wife and I were returning home
from visiting our daughter at college. About 30 miles into the trip, on a smooth highway, the entire car suddenly shut down while we were traveling at 60 mph. No
engine, no headlights, no instrument lights, no nothing. I tried restarting the car, but it wouldn't restart. As I was trying to bring the car to a safe stop, everything
suddenly came back on. I restarted the engine, and we made it the rest of the way home without incident.

Needless to say, though, it was a pretty tense 20 seconds or so! Any ideas what to look for? I talked to the local Pontiac dealer who said that if everything except the
engine died, then it could be the "body control module." But the engine DID die. I don't want to just let him go wild at $60/hour. How do you suggest we solve this
mystery? -- Ken

RAY: Well, congratulations on already solving one mystery, Ken. Now you know why the previous owner sold this car!

TOM: This is a tough one. But if I had to guess, I'd say you had an interruption of current at the fire wall. The fire wall is the wall that separates the engine
compartment from the passenger compartment.

RAY: Right. And all the electrical current that makes the car work -- including the current for the engine -- has to pass through the fire wall.

TOM: I can't remember the wiring details of the '94 SSEi, but most cars have several electrical harnesses that run right through the fire wall. And my guess is that you
have a loose connection there.

RAY: With the engine running, ask your mechanic to start by shaking all of the wires in these harnesses on both sides of the fire wall. If you can cause the failure to
occur by shaking the wires, that'll give you a pretty good hint as to where the problem is.

TOM: But if this test doesn't yield any information, then you're going to have to start replacing stuff, because this problem is dangerous. And I'd start with the body
control and engine control modules.

Why do unmitigated cheapskates like Tom continue to buy nothing but old clunkers? Find out by reading Tom and Ray's guide "How to Buy a Great Used Car: Things
Detroit and Tokyo Don't Want You to Know." To order, send $3 and a stamped (55 cents), self-addressed, No. 10 envelope to Used Car, PO Box 6420, Riverton, NJ

?(C) 1999 by Tom and Ray Magliozzi and Doug Berman
Distributed by King Features Syndicate, Inc.

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